Effects of annealing on structures and properties of Cu-Hf-Al amorphous thin films

We have investigated the formation of Cu-based amorphous alloy film in Cu-Hf-Al ternary system and the effect of annealing temperature on the mechanical, electrical and electrochemical properties. The films with a composition of Cu72.4Hf18.4Al9.2 were prepared using a DC magnetron sputtering method. We found that the glass transition temperature Tg of the Cu-Hf-Al amorphous film is around 550 °C. Upon annealing at temperatures above Tg, the films displayed (partial) crystallization and remarkable changes in mechanical properties and electrical resistance. The Cu-Hf-Al amorphous thin film exhibited high Young's modulus of 127.1 GPa and hardness of 7.2 GPa, and has a strong passivation ability and high corrosion resistance in H+ or Na+ environments.